1. Field of the Invention
The present invention relates to a package inspecting system for automatically inspecting the package of a product to determine if the product is properly packaged.
2. Description of the Prior Art
An exemplary package inspecting system according to the prior art will be discussed with reference to FIG. 1 which also shows one of preferred embodiments of the present invention. Referring to FIG. 1, quantities of articles M successively discharged from a combination weighing apparatus 1 and then falling onto a chute 203 are successively packaged by a combined bagging and packaging machine 200. The combined bagging and packaging machine 200 includes a vertical sealer (a vertical sealing device) 201 for sealing together opposite longitudinal side edges of a web of film F that is used as a packaging material so that that web of film F can be formed into a tubular form, and an end sealer (an end sealing device) 202 for thermally sealing a downwardly oriented end of the tubular film F and also for subsequently thermally sealing and cutting an upwardly oriented end F1 of the tubular film F after the individual quantity of the articles M have been received within the tubular film F, thereby producing a bagged product M1. Thus, the combined bagging and packaging machine 200 successively produces bagged products M1 each containing the quantity of the articles M, and the bagged products M1 so produced are successively transported to a weight checker 300 that checks the bagged products M1 one at a time to determine if the weight of the articles M in each bagged product M1 falls within an acceptable tolerance. After the bagged products M1 have been checked at to their weight by the weight checker 300, the bagged products M1 are successively transported to a seal checker 400 where a sealing condition of each of the bagged products M1 is checked.
It has, however, been found that mere inspection of the sealing condition of the respective bagged product M1 is ineffective to provide an indication of which one of the longitudinal side sealer 201 and the end sealer 202 has failed to operate properly. In order to specify one of the longitudinal side sealer 201 and the end sealer 202 that has in effect failed to operate properly, a problem has hitherto been encountered in that substantial amounts of labor and time are required, resulting in reduction in productivity of the system as a whole.
Accordingly, the present invention has for its primary object to facilitate identification of one of the sealers that has failed to operate properly so that the productivity of the package inspecting system and the yield of the bagged products being produced can be increased.
To this end, the present invention in one aspect thereof provides a package inspecting system which includes a packaging machine and a seal checker for inspecting a sealing condition of the packaging material of the bagged product. The package inspecting system also includes a bite detecting means provided in the packaging machine for detecting whether or not the articles are bitten in the end of the packaging material. In this construction, the presence or absence of an abnormal condition or a content of abnormality in each of the sealing devices is diagnosed based on a result of detection, performed by the bite detecting means, and a result of inspection performed by the seal checker with respect to the same bagged product.
With this structure according to the present invention, by diagnosing the presence or absence of abnormality in one or both of the sealing devices based on the result of detection, performed by the bite detecting means, and the result of inspection performed by the seal checker with respect to the same bagged product, and then by indicating the result of diagnosis, an operator can quickly diagnose (determine) the presence or absence of abnormality in one of the sealing devices for forming the longitudinal side seal and the end seal and, also, the presence or absence of abnormality in the seal checker. Accordingly, the productivity of the system and the yield of production of the bagged products can be increased. Moreover, since the above described diagnosis can be implemented in a simple manner merely by adding a microcomputer executable program, the cost will not increase so much.
Preferably, the result of diagnosis can be informed by an indicating means.
The bite detecting means detects whether or not a bite has occurred at an end of the packaging material (i.e., an end of the packaging material in a longitudinal direction of the bagged product). On the other hand, the seal checker detects the presence or absence of leakage (i.e., leakage of air) from the packing material of the bagged product. If the articles are bitten in the sealed portion of the packaging material, leakage generally occurs. Accordingly, where with respect to the same bagged product leakage occurs although no bite has been detected, it can be generally inferred that a trouble may have occurred in the vertical sealing device.
The term xe2x80x9carticle (or articles)xe2x80x9d hereinbefore and hereinafter employed is intended to mean an aggregation of items that are weighed and bagged, and the term xe2x80x9cbagged productxe2x80x9d is intended to mean the aggregation that has been bagged. The wording xe2x80x9cto diagnosis an abnormal condition or a content of abnormalityxe2x80x9d is intended to mean presumption or estimation in any way whatsoever in connection with abnormality of any one of the sealing devices and, for example, presumption of which one of the sealing devices has suffered from an abnormal condition. The term xe2x80x9cindicating meansxe2x80x9d is intended to encompass, for example, a liquid crystal display device, a cathode ray tube display device or a warning lamp.
According to another aspect of the present invention, there is provided a package inspecting system including a packaging machine, a weight checker, a seal checker for inspecting a sealing condition of the packaging material of the bagged product, a determining means for diagnosing the abnormal condition or the content of abnormality occurring in each of the sealing devices based on respective results of detection and inspection performed by the seal checker and the weight checker with respect to the same bagged product, and an indicating means operable to indicate a result of the diagnosis.
According to still another aspect of the present invention, by diagnosing the presence or absence of abnormality in one or both of the sealing devices based on the result of detection performed by the weight checker and the result of inspection performed by the seal checker with respect to the same bagged product, and then by indicating the result of diagnosis, an operator can quickly ascertain the presence or absence of abnormality in one of the sealing devices for forming the longitudinal side seal and the end seal. Accordingly, the productivity of the system and the yield of production of the bagged products can be increased. Moreover, since the above-described diagnosis can be implemented in a simple manner merely by adding a microcomputer executable program, the cost will not increase very much.
In this alternative system, depending on the overweight and the underweight detected by the weight checker, for example, depending on whether or not excess and deficiency of the bagged product weighed previously and those of the bagged product weighed currently have a complemental relation with each other (which is hereinafter referred to as xe2x80x9cfore-and-aft symptomxe2x80x9d), it is determined which one of the vertical sealing and end sealing devices is abnormal in operation.
The term xe2x80x9cto have a complemental relationshipxe2x80x9d means that an overweight and an underweight are found in the advancing and following bagged products and, at the same time, the sum of the excess and deficiency of the previously weighed bagged product and the excess and deficiency of the currently weighed bagged product is equal to or close to zero.
Such complemental relation occurs in the following case. Specifically, if the weighing and packaging speeds are increased, the advancing articles falling and the aggregation of the following articles are close to each other. Accordingly, if the timing of the end seal of the bag deviates, a portion of the following articles may mingle into the advancing articles or a portion of the advancing articles may mingle into the following articles. The complemental relation occurs when the articles are bagged with a portion of the advancing or following articles being mingled into the following or advancing articles, respectively. This tendency often occurs where the articles are relatively bulky and may result from the fact that the articles falling through a portion of a chute, which forms a bottleneck, are braked. Accordingly, where with respect to the same bagged product, a defective seal occurs as determined by the seal checker and, at the same time, the fore-and-aft symptom occurs, it can be inferred that the defective seal has been caused as a result of a delay in sealing timing of the end sealing device. On the other hand, if the defective seal as determined by the seal checker is repeated continuously and, at the same time, no fore-and-aft symptom occurs, it can be inferred that the defective seal has been caused as a result of, for example, a lowering of the temperature in one of the vertical sealing device and the end sealing device.
In addition to the results of inspection performed by the checkers, if the previously described determination is carried out relying on whether the result of inspection performed by the seal checker indicating unacceptable is repeated continuously, the reliability of determination can be increased.